Finding corresponding features in images is an essential component of almost any vision application that tries to extract information from more than one image. For example, vision applications such as image matching and view-based object recognition rely on finding corresponding features in images.
A key step in many methods for finding these corresponding features is to identify so called interest points. In general, an ideal interest point can be defined as a point in an image having a well-defined, often sub-pixel, location in image space, with a local neighborhood that is rich in distinguishing information, and which is substantially invariant to changes in perspective as well as variation in illumination and brightness. Such interest points provide a high degree of repeatability in that the same points are detected in images of the same scene depicting the point, even under different imaging conditions.